1. Intestinal Obstruction
Ahmed Badrek-Amoudi FRCS

2. The common Scenario
A 50 year old gentleman presents
with abdominal pain, distension and
absolute constipation. With
repeated episodes of vomiting.
His vital sign were stable, abdomen
distended with diffuse tenderness
but minimal peritonism. Bowel
Sounds are hyperactive.
The plain abdominal xray was taken
on admission.

3. What are your objectives?
You should be able to address the following questions
1. Is this bowel obstruction or ileus?
2. Is this a small or large bowel obstruction?
3. Is this proximal or distal obstruction?
4. What is the cause of this obstruction?
5. Is this a complex or simple obstruction?
6. How should I start investigating my patient?
7. What is the role of other supportive investigations?
8. What is my immediate/ intermediate treatment plan?
9. What are the indications for surgery?
10. What are the medico-legal and ethical issues that I
should address?

4. Introduction and Definitions
Accounts for 5% of all acute surgical admissions
Patients are often extremely ill requiring prompt
assessment, resuscitation and intensive monitoring
Obstruction A mechanical blockage arising from a
structural abnormality that presents a
physical barrier to the progression of gut
contents.
Ileus is a paralytic or functional variety of
obstruction
Obstruction is: Partial or complete
Simple or strangulated

5. Patho-physiology I
 8L of isotonic fluid received by the small intestines
(saliva, stomach, duodenum, pancreas and hepatobiliary )
 7L absorbed
 2L enter the large intestine and 200 ml excreted in the
faeces
 Air in the bowel results from swallowed air ( O2 & N2) and
bacterial fermentation in the colon ( H2, Methane & CO2),
600 ml of flatus is released
 Enteric bacteria consist of coliforms, anaerobes and
strep.faecalis.
 Normal intestinal mucosa has a significant immune role
 Distension results from gas and/ or fluid and can exert
hydrostatic pressure.
 In case of BO Bacterial overgrowth can be rapid
 If mucosal barrier is breached it may result in translocation of
bacteria and toxins resulting in bactaeremia, septaecemia and
toxaemia.

6. Patho-physiology II
Obstruction results in:
1. Initial overcoming of the obstruction by increased
paristalsis
2. Increased intraluminal pressure by fluid and gas
3. Vomiting
4. sequestration of fluid into the lumen from the surrounding
circulation
5. Lymphatic and venous congestion resulting in oedematous
tissues
6. Factors 3,4,5 result in hypovolaemia and electrolyte
imbalance
7. Further: localised anoxia, mucosal depletion necrosis and
perforation and peritonitis.
8. Bacterial over growth with translocation of bacteria and it’s
toxins causing bacteraemia and septicaemia.
 Decompress with NGT
 Replace lost fluid
 Correct electrolyte abnormalities
 Recognise strangulation and perforation
 Systemic antibiotics.

7. Causes- Small Bowel
Luminal Mural Extraluminal
F. Body Neoplasims Postoperative
Bezoars lipoma adhesions
Gall stone polyps
Food Particles leiyomayoma Congenital
A. lumbricoides hematoma adhesions
lymphoma
carcimoid Hernia
carinoma
secondary Tumors Volvulus
Crohns
TB
Stricture
Intussusception
Congenital

8. Small Bowel Adhesions
• Accounts for 60-70% of All SBO
• Results from peritoneal injury, platelet activation and fibrin
formation.
• Associated with starch covered gloves, intraperitoneal sepsis,
haemorrhage and wash with irritant solutions iodine and other
foreign bodies.
• As early as 4 weeks post laparotomy. The majority of patients
present between 1-5 years
• Colorectal Surgery 25%
• Gynaecological 20%
• Appendectomy 14%
• 70% of patients had a single band
• Patients with complex bands are more likely to be readmitted
• Readmission in surgically treated patients is 35%

9. ADHESIVE INTESTINAL OBSTRUCTION

10. ADHESIVE INTESTINAL OBSTRUCTION

11. ADHESIVE INTESTINAL OBSTRUCTION

12. ADHESIVE INTESTINAL OBSTRUCTION

13. ADHESIVE INTESTINAL OBSTRUCTION

14. Hernia
• Accounts for 20% of SBO
• Commonest 1. Femoral hernia
2. ID inguinal
3. Umbilical
4. Others: incisional and internal H.
• The site of obstruction is the neck of hernia
• The compromised viscus is with in the sac.
• Ischaemia occurs initially by venous occlusion,
followed by oedema and arterialc ompromise.
• Attempt to distinguish the difference between:
• Incaceration
• Sliding
• Obstruction
• Strangulation is noted by:
» Persistent pain
» Discolouration
» Tenderness
» Constitutional symptoms

15. Other causes
Intussusception Gall stone Ileus IBD

16. INTUSSUSCEPTION
Inversion of the bowel upon itself secondary to
a leading point
Juvenile Intussusception most often idiopathic
Also secondary to Meckel"s diverticulum
Presents 6 months to 2 years of age
As early as 1 month
Acute painful episodes followed by periods of
lethargy
When incarcerated progress to continuous
lethargy
May or may not have “currant-jelly” stool
But often stool is heme positive
Rule out with a left lateral Decubitus film

17. Bad Intussusception

18. Intussusception

19. Large Bowel Obstruction
•Distinguishing ileus from mechanical obstruction is challenging
•According to Leplac’s law: maximum pressure is at the it’s
maximum diameter. Cecum is at the greatest risk of perforation
•Perforation results in the release of formed feaces with heavy
bacterial contamination
Aetiology:
1. Carcinoma: The commonest cause, 18% of colonic ca. present
with obstruction
2. Benign stricture: Due to Diverticular disease, Ischemia,
Inflammatory bowel disease.
3. Volvulus: 1. Sigmoid Volvulus: Results from long redundant,
faecaly loaded colon with a narrow pedicle
2. Caecal Volvulus
4. Hernia.
5. Congenital : Hirschusbrung, anal stenosis and agenesis

20. Sigmoid Volvulus Colonic Obstruction

21. Radiological Evaluation
Normal Scout
Always request: Supine, Erect and CXR
Gas pattern:
• Gastric,
• Colonic and 1-2 small bowel
Fluid Levels:
• Gastric
• 1-2 small bowel
Check gasses in 4 areas:
1. Caecal
2. Hepatobiliary
3. Free gas under diaphragm
4. Rectum
Look for calcification
Look for soft tissue masses, psoas shadow
Look for fecal pattern

22. The Difference between small
and large bowel obstruction
Large bowel Small Bowel
•Peripheral ( diameter 8 cm max) •Central ( diameter 5 cm max)
•Presence of haustration •Vulvulae coniventae
•Ileum: may appear tubeless

23. Symptoms
The four cardinal features of intestinal obstruction:
-abdominal pain
-vomiting
-distension
-constipation
Vary according to:-
location of obstruction
age of obstruction
underlying pathology
intestinal ischemia

24. Symptoms
Abdominal pain
colicky in nature, around the umbilicus in SBO while in
the lower abdomen in LBO
if it becomes continuous, think about perforation or
strangulation
Vomiting
-starts early in SBO and late in LBO
-vomitus starts with clear color then becomes thick, brown
and foul ( faeculent)
-more with lower or complete obstruction
-diarrhea may be present with partial obstruction
Distension
-more with lower obstruction

25. Symptoms
Constipation
-more with lower or complete obstruction
-diarrhea may be present with partial obstruction
-either absolute (no feces or flatus)<-cardinal in absolute
IO
or relative (flatus passed)
Distension
-more with lower obstruction

26. Symptoms
In strangulation:
severe constant abdominal pain •
distended abdomen •
fever •
tachycardia •
tender abdomen •

27. Role of CT
• Used with iv contrast, oral and
rectal contrast (triple contrast).
• Able to demonstrate
abnormality in the bowel wall,
mesentery, mesenteric vessels
and peritoneum.
• It can define
– the level of obstruction
– The degree of obstruction
– The cause: volvulus,
hernia, luminal and mural
causes
– The degree of ischaemia
– Free fluid and gas
• Ensure: patient vitally stable
with no renal failure and no
previous alergy to iodine

28. Role of barium gastrografin
studies
Barium should not be used in
a patient with peritonitis
• As: follow through, enema
• Limited use in the acute
setting
• Gastrografin is used in
acute abdomen but is
diluted
• Useful in recurrent and
chronic obstruction
• May able to define the level
and mural causes.
• Can be used to distinguish
adynamic and mechanical
obstruction

29. How to initially investigate
your patient
• Lab:
• CBC (leukocytosis, anaemia, hematocrit, platelets)
• Clotting profile
• Arterial blood gasses
• U& Crt, Na, K, Amylase, LFT and glucose, LDH
• Group and save (x-match if needed)
• Optional (ESR, CRP, Hepatitis profile
• Radilogical:
• Plain xrays
• USS ( free fluid, masses, mucosal folds, pattern of
paristalsis, Doppler of mesenteric vasulature, solid organs)
• Other advanced studies (CT, MRI, Contrast studies……senior
decision)
• ECG and other investigations for co-morbid factors

30. Understanding the
clinical findings

31. Clinical Findings
1. History
The Universal Features
Colicky abdominal pain, vomiting, constipation (absolute), abdominal
distension.
Complete HX ( PMH, PSH, ROS, Medication, FH, SH)
High Distal small bowel Colonic
•Pain is rapid •Pain: central and •? Preexisting change
colicky in bowel habit
•Vomiting copious and •Vomitus is feculunt •Colicky in the lower
contains bile jejunal •Distension is severe abdomin
content •Vomiting is late
•Visible peristalsis
•May continue to pass •Distension prominent
•Abdominal distension
is limited or localized
flatus and feacus •Cecum ? distended
before absolute
constipation
•Rapid dehydration
• Persistent pain may be a sign of strangulation
• Relative and absolute constipation

32. Clinical Findings
2. Examination
General Abdominal Others
•Vital signs: •Abdominal Systemic examination
P, BP, RR, T, Sat distension and it’s If deemed necessary.
pattern •CNS
•dehydration
•Hernial orifices •Vascular
•Anaemia, jaundice,
•Visible peristalsis •Gynaecological
LN
•Cecal distension •muscuoloskeltal
•Assessment of
•Tenderness,
vomitus if possible
guarding and
•Full lung and heart rebound
examination •Organomegaly
•Bowel sounds
–High pitched
–Absent
•Rectal examination

33. Initial Management in the ER
• Resuscitate:
• Air way (O2 60-100%)
• Insert 2 lines if necessary
• IVF : Crytloids at least 120 ml/h. (determined by estimated fluid
loss and cardiac function). Add K+ at 1mmmol/kg
• Draw blood for lab investigations
• Inform a senior member in the team.
• NPO.
• Decompress with Naso-gastric tube and secure in position
• Insert a urinary catheter (hourly urinary measurements) and
start a fluid input / output chart
• Intravenous antibiotics (no clear evidence)
• If concerns exist about fluid overloading a central line should be
inserted
• Follow-up lab results and correction of electrolyte imbalance
• The patient should be nursed in intermediate care
• Rectal tubes should only be used in Sigmoid volvulus.

34. Indications for Surgery
Immediate intervention:
• Evidence of strangulation (hernia….etc)
• Signs of peritonitis resulting from perforation or ischemia
In the next 24-48 hours
• Clear indication of no resolution of obstruction ( Clinical,
radiological).
• Diagnosis is unclear in a virgin abdomen
Intermediate stage
The cause has been diagnosed and the patient is stabalised

35. Legal issues and consent

36. Ileus
• Associated with the following conditions:
• Postoperative and bowel resection
• Intraperitoneal infection or inflammation
• Ischemia
• Extra-abdominal: Chest infection, Myocardia infarction
• Endocrine: hypothyroidism, diabetes
• Spinal and pelvic fractures
• Retro-peritoneal haematoma
• Metabolic abnormalities:
» Hypokalaemia
» Hyponatremia
» Uraemia
» Hypomagnesemia
• Bed ridden
• Drug induced: morphine, tricyclic antidepressants

37. Is this an ileus or
obstruction
Clinical features
• Is there an under lying cause?
• Is the abdomen distended but tenderness is not marked.
• Is the bowel sounds diffusely hypoactive.
Radiological features:
• Is the bowel diffusely distended
• Is there gas in the rectum
• Are further investigasions (CT or Gastrografin studies) helpful
in showing an obstruction.
Does the patient improve on conservative measures

38. Example of ileus